The present invention relates to useful gelatinous elastomer compositions and articles.
This application is based upon subject matters described in earlier filed and copending related applications and patents (see Related Applications above) which are specifically incorporated herein by reference.
As taught in related U.S. Pat. No. 4,369,284, No. 4,618,213 and No. 5,153,254, oil extended thermoplastic block copolymers of the prior art suffer certain poor properties. Shell Technical Bulletin No. SC 65-75 teaches the use of low viscosity poly(styrene-ethylene-butylene-styrene) triblock copolymers (Kraton G 1650 and G 1652) with Brookfield Viscosities of 1,500 and 550 cps (viscosity being measured for a solution of 20 weight percent solids in toluene at 250xc2x0 C.) plasticized with oil, the compositions obtained trend to rupture and crumble when submitted to moderate shearing stress conditions.
The advantages and inherent properties of the gelatinous elastomer compositions (herein interchangeably refer to as xe2x80x9cgelatinous compositionsxe2x80x9d or simply as xe2x80x9cgel compositionsxe2x80x9d or more simply as xe2x80x9cgelsxe2x80x9d) and articles of the invention are many. The gel compositions exhibits high dimensional stability, crack, tear, craze, and creep resistance, excellent tensile strength and high elongation, long service life under stress and capable of repeated handling, excellent processing ability for cast molding, non-toxic, nearly tasteless and odorless, extremely soft and strong, highly flexible, possessing elastic memory, substantially with little or no plasticizer bleedout. The gel can also be made transparent. The desirable combination of physical properties are unexpected.
In a first embodiment, the composites of the invention comprises a thermoplastic, heat formable and heat reversible gelatinous elastomer composition, G, which is formed into a composite by heat and interlocked with one or more of a selected substrate material, M, said gelatinous elastomer composition formed from
(i) 100 parts by weight of one or a mixture of two or more of a hydrogenated styrene isoprene/butadiene block copolymer(s) and from
(ii) about 300 to about 1,600 parts by weight of a plasticizing oil; said gelatinous elastomer compositions characterized by a gel rigidity of from about 20 to about 800 gram Bloom; wherein said block copolymers have the general configuration A-B-A wherein A is a glassy polymer end block segment of polystyrene and B is an elastomeric polymer center block segment of (ethylene-ethylene-propylene) and said gel being in combination with or without
(iii) a selected amount of one or more polymers or copolymers of poly(styrene-butadiene-styrene), poly(styrene-butadiene)n, poly(styrene-isoprene-styrene)n, poly(styrene-isoprene)n, poly(styrene-ethylene-propylene), poly(styrene-ethylene-propylene-styrene), poly(styrene-ethylene-butylene-styrene), poly(styrene-ethylene-butylene), poly(styrene-ethylene-propylene)n, poly(styrene-ethylene-butylene)n, polystyrene, polybutylene, poly(ethylene-propylene), poly(ethylene-butylene), polypropylene, or polyethylene, wherein said selected copolymer is a linear, radial, star-shaped, branched or multiarm copolymer, wherein n is greater than one; and wherein said composite formed from the combination GnMn, GnMnGn, MnGnMn, GnGnMn, MnMnMnGn, MnMnMnGnMn, MnGnGnMn, GnMnGnGn, GnMnMnGn, GnGnMnMn, GnGnMnGnMn, GnMnGnMnMn, MnGnMnGnMnGn, GnGnMnMnGn, GnGnMnGnMnGn, a sequential addition or a permutation of one or more of said Gnwith Mn; wherein when n is a subscript of M, n is the same or different selected from the group consisting of foam, plastic, fabric, metal, concrete, wood, glass, ceramics, synthetic resin, synthetic fibers or refractory materials; and wherein when n is a subscript of G, n denotes the same or a different gel rigidity of from about 20 to about 800 gram Bloom.
More generally, the invention comprises thermoplastic, heat formable and heat reversible gelatinous elastomer compositions and articles formed from (I) 100 parts by weight of one or more hydrogenated styrene block copolymers having 2-methyl-1,3-butadiene and 1,3-butadiene blocks of the formula poly(styrene-ethylene-ethylene-propylene-styrene) and optionally in combination with (II) a selected amount of one or more selected polymer or copolymer; (III) from about 300 to about 1,600 parts by weight of a plasticizing oil; said gelatinous elastomer compositions being characterized by a gel rigidity of from about 20 to about 800 gram Bloom.
Useful articles can be formed from the gelatinous elastomer compositions of the invention, including molded articles, composites (gel compositions xe2x80x9cinterlockedxe2x80x9d with various substrates), articles having sticking and non-sticking properties, strong oriented gel compositions as view in polarized light etc.
The various aspects and advantages of the invention will become apparent to those skilled in the art upon consideration of the accompanying disclosure.